Online buying and selling of products and services over computer networks, such as the Internet, have continued to proliferate with widespread Internet usage. In order to facilitate the sale of products and services, online sellers of products and services often design marketing campaigns wherein a given campaign message, such as an email, text message and/or instant message, is sent to a given set of recipients.
With the proliferation of email marketing, an industry of Email Service Providers (ESPs) has emerged. An ESP is an entity that provides email marketing or bulk email services. An ESP may provide tracking information showing the status of email sent to each member of an address list. ESPs also often provide the ability to segment an address list into interest groups or categories, allowing a sender to send targeted information to recipients who they believe will value the email. ESPs typically upload subscriber lists from senders for distributing email messages. The lists may be enhanced with custom fields in order to hold additional information for each subscriber for filtering and targeted messaging purposes. A sending engine also may be provided to allow senders to distribute their messages to the subscribers via the ESP.